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* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v1 5/7] Row pattern recognition patch (docs).
@ 2023-06-25 11:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-25 11:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 51 ++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 18 ++++++++--
3 files changed, 136 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..23ee285b40 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,57 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..c0fc16d773 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,20 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses.
+
+<synopsis>
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Jun_25_21_05_09_2023_126)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v1-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An
+ example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v3 5/7] Row pattern recognition patch (docs).
@ 2023-07-26 10:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-07-26 10:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++++++--
3 files changed, 133 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index dcc9d6f59d..b333d62410 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21714,6 +21714,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21753,6 +21754,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,31 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Jul_26_21_21_34_2023_317)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v3-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v4 5/7] Row pattern recognition patch (docs).
@ 2023-08-09 07:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-08-09 07:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index be2f54c914..6cda164522 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21715,6 +21715,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21754,6 +21755,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Aug__9_17_41_12_2023_134)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v4-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v5 5/7] Row pattern recognition patch (docs).
@ 2023-09-02 06:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-02 06:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7a0d4b9134..b7bfc9271e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21772,6 +21772,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21811,6 +21812,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Sep__2_15_52_35_2023_273)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v5-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs).
@ 2023-09-12 05:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..eda3612822 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..8d3becd57a 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Sep_12_15_18_43_2023_359)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v6-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v7 5/7] Row pattern recognition patch (docs).
@ 2023-09-22 04:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-22 04:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Sep_22_14_16_40_2023_530)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v7-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v8 5/7] Row pattern recognition patch (docs).
@ 2023-09-25 05:01 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-09-25 05:01 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 24ad87f910..9c99dda4ae 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 0ee0cc7e64..056768b330 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1074,6 +1074,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Sep_25_14_26_30_2023_752)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v8-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v9 5/7] Row pattern recognition patch (docs).
@ 2023-10-04 05:51 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-04 05:51 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++--
3 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..f39ec8f2d5 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used with row pattern common syntax to
+ perform row pattern recognition in a query. Row pattern common syntax
+ includes two sub clauses. <literal>DEFINE</literal> defines definition
+ variables along with an expression. The expression must be a logical
+ expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. An example
+ of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, max(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f1ad64c3d6..6c46ea4355 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21819,6 +21820,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Oct__4_15_03_28_2023_821)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v9-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v10 5/7] Row pattern recognition patch (docs).
@ 2023-10-22 02:22 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 7c3e940afe..1d835af15a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21878,6 +21878,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21917,6 +21918,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Oct_22_11_39_20_2023_140)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v10-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v11 5/7] Row pattern recognition patch (docs).
@ 2023-11-08 06:57 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-11-08 06:57 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d963f0a0a0..c3a8167c8e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21933,6 +21933,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21972,6 +21973,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 42d78913cf..522ad9dd70 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_Nov__8_16_37_05_2023_872)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v11-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec__4_20_40_48_2023_532)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v12 5/7] Row pattern recognition patch (docs).
@ 2023-12-04 11:23 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2023-12-04 11:23 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 20da3ed033..8a18e0ee23 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21935,6 +21935,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21974,6 +21975,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 227ba1993b..dabaca9127 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Dec__8_10_16_13_2023_489)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v12-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v13 6/8] Row pattern recognition patch (docs).
@ 2024-01-22 09:45 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-01-22 09:45 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 210c7c0b02..8422aa6b93 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21941,6 +21941,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -21980,6 +21981,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Jan_22_19_26_18_2024_011)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v13-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v14 6/8] Row pattern recognition patch (docs).
@ 2024-02-28 13:59 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-02-28 13:59 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e5fa82c161..8dd97501a7 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22364,6 +22364,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22403,6 +22404,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 9917df7839..1575fc2167 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Feb_29_09_19_54_2024_640)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v14-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v15 6/8] Row pattern recognition patch (docs).
@ 2024-03-28 10:30 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-03-28 10:30 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 93b0bc2bc6..d25eeb3327 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -22637,6 +22637,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -22676,6 +22677,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Mar_28_19_59_25_2024_076)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v15-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v17 6/8] Row pattern recognition patch (docs).
@ 2024-04-28 11:00 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-04-28 11:00 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 1928de5762..adbcb1f279 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sun_Apr_28_20_28_26_2024_444)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v17-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v18 6/8] Row pattern recognition patch (docs).
@ 2024-05-11 07:11 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-11 07:11 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_May_11_16_23_07_2024_789)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v18-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v19 6/8] Row pattern recognition patch (docs).
@ 2024-05-14 23:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-14 23:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Wed_May_15_09_02_03_2024_008)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v19-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v20 6/8] Row pattern recognition patch (docs).
@ 2024-05-24 02:26 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-05-24 02:26 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 17c44bc338..8dbab31300 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23124,6 +23124,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23163,6 +23164,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_May_24_11_39_19_2024_763)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v20-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v21 6/8] Row pattern recognition patch (docs).
@ 2024-08-26 04:32 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-08-26 04:32 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 461fc3f437..02ad2b0195 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23258,6 +23258,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23297,6 +23298,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Aug_26_13_39_47_2024_878)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v21-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v22 6/8] Row pattern recognition patch (docs).
@ 2024-09-19 04:48 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-09-19 04:48 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6f75bd0c7d..4482c80a70 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23261,6 +23261,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23300,6 +23301,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Sep_19_13_59_47_2024_608)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v22-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v23 6/8] Row pattern recognition patch (docs).
@ 2024-10-25 03:56 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-10-25 03:56 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 58dc06b68b..ef4fa7144f 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23263,6 +23263,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23302,6 +23303,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Oct_25_13_04_53_2024_648)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v23-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v24 6/8] Row pattern recognition patch (docs).
@ 2024-12-19 06:06 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-19 06:06 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Thu_Dec_19_15_19_50_2024_894)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v24-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v25 6/9] Row pattern recognition patch (docs).
@ 2024-12-21 06:19 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-21 06:19 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Sat_Dec_21_18_20_04_2024_526)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v25-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v26 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 12:44 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 12:44 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Mon_Dec_30_22_37_18_2024_171)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v26-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v27 6/9] Row pattern recognition patch (docs).
@ 2024-12-30 23:53 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Tatsuo Ishii @ 2024-12-30 23:53 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 82 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 172 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..b0b1d1c51e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,88 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. The row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. Thus in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. On the second or
+ subsequent rows all window functions are NULL. Aggregates are NULL or 0
+ (count case) depending on its aggregation definition. For rows that do not
+ match on the PATTERN, all window functions and aggregates are shown AS
+ NULL too, except count showing 0. This is because the rows do not match,
+ thus they are in an empty frame. Example of a <literal>SELECT</literal>
+ using the <literal>DEFINE</literal> and <literal>PATTERN</literal> clause
+ is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | | 0
+ company1 | 2023-07-03 | 150 | | | 0
+ company1 | 2023-07-04 | 140 | | | 0
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | | 0
+ company1 | 2023-07-08 | 130 | | | 0
+ company1 | 2023-07-09 | 120 | | | 0
+ company1 | 2023-07-10 | 130 | | | 0
+(10 rows)
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 47370e581a..17a38c4046 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23338,6 +23338,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23377,6 +23378,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index d7089eac0b..7e1c9989ba 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Tue_Dec_31_08_57_07_2024_963)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v27-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
* [PATCH v50 2/8] Rename cluster.c/h -> repack.c/h
@ 2026-03-31 16:55 Álvaro Herrera <[email protected]>
0 siblings, 0 replies; 839+ messages in thread
From: Álvaro Herrera @ 2026-03-31 16:55 UTC (permalink / raw)
---
src/backend/commands/Makefile | 2 +-
src/backend/commands/matview.c | 2 +-
src/backend/commands/meson.build | 2 +-
src/backend/commands/{cluster.c => repack.c} | 6 +++---
src/backend/commands/tablecmds.c | 2 +-
src/backend/commands/vacuum.c | 6 +++---
src/backend/storage/ipc/procsignal.c | 1 +
src/backend/tcop/postgres.c | 1 +
src/backend/tcop/utility.c | 2 +-
src/include/commands/{cluster.h => repack.h} | 12 ++++++------
10 files changed, 19 insertions(+), 17 deletions(-)
rename src/backend/commands/{cluster.c => repack.c} (99%)
rename src/include/commands/{cluster.h => repack.h} (90%)
diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index c10fdba2bbb..fe1bba3a9b9 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -18,7 +18,6 @@ OBJS = \
amcmds.o \
analyze.o \
async.o \
- cluster.o \
collationcmds.o \
comment.o \
constraint.o \
@@ -51,6 +50,7 @@ OBJS = \
proclang.o \
propgraphcmds.o \
publicationcmds.o \
+ repack.o \
schemacmds.o \
seclabel.o \
sequence.o \
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index d3be8939011..5db4fe75dce 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -24,8 +24,8 @@
#include "catalog/namespace.h"
#include "catalog/pg_am.h"
#include "catalog/pg_opclass.h"
-#include "commands/cluster.h"
#include "commands/matview.h"
+#include "commands/repack.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
#include "executor/executor.h"
diff --git a/src/backend/commands/meson.build b/src/backend/commands/meson.build
index 90c7e37a429..f624aae74af 100644
--- a/src/backend/commands/meson.build
+++ b/src/backend/commands/meson.build
@@ -6,7 +6,6 @@ backend_sources += files(
'amcmds.c',
'analyze.c',
'async.c',
- 'cluster.c',
'collationcmds.c',
'comment.c',
'constraint.c',
@@ -39,6 +38,7 @@ backend_sources += files(
'proclang.c',
'propgraphcmds.c',
'publicationcmds.c',
+ 'repack.c',
'schemacmds.c',
'seclabel.c',
'sequence.c',
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/repack.c
similarity index 99%
rename from src/backend/commands/cluster.c
rename to src/backend/commands/repack.c
index f241e18b153..20f0a572236 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/repack.c
@@ -1,6 +1,6 @@
/*-------------------------------------------------------------------------
*
- * cluster.c
+ * repack.c
* REPACK a table; formerly known as CLUSTER. VACUUM FULL also uses
* parts of this code.
*
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * src/backend/commands/cluster.c
+ * src/backend/commands/repack.c
*
*-------------------------------------------------------------------------
*/
@@ -33,9 +33,9 @@
#include "catalog/pg_am.h"
#include "catalog/pg_inherits.h"
#include "catalog/toasting.h"
-#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/progress.h"
+#include "commands/repack.h"
#include "commands/tablecmds.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 0ce2e81f9c2..e2882a50b3b 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -57,10 +57,10 @@
#include "catalog/storage.h"
#include "catalog/storage_xlog.h"
#include "catalog/toasting.h"
-#include "commands/cluster.h"
#include "commands/comment.h"
#include "commands/defrem.h"
#include "commands/event_trigger.h"
+#include "commands/repack.h"
#include "commands/sequence.h"
#include "commands/tablecmds.h"
#include "commands/tablespace.h"
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 0ed363d1c85..b179b62b5c8 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -9,7 +9,7 @@
*
* VACUUM for heap AM is implemented in vacuumlazy.c, parallel vacuum in
* vacuumparallel.c, ANALYZE in analyze.c, and VACUUM FULL is a variant of
- * CLUSTER, handled in cluster.c.
+ * REPACK, handled in repack.c.
*
*
* Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
@@ -38,9 +38,9 @@
#include "catalog/pg_database.h"
#include "catalog/pg_inherits.h"
#include "commands/async.h"
-#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/progress.h"
+#include "commands/repack.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
@@ -2293,7 +2293,7 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams params,
if ((params.options & VACOPT_VERBOSE) != 0)
cluster_params.options |= CLUOPT_VERBOSE;
- /* VACUUM FULL is a variant of REPACK; see cluster.c */
+ /* VACUUM FULL is a variant of REPACK; see repack.c */
cluster_rel(REPACK_COMMAND_VACUUMFULL, rel, InvalidOid,
&cluster_params);
/* cluster_rel closes the relation, but keeps lock */
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index 7e017c8d53b..7cef6e43661 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -19,6 +19,7 @@
#include "access/parallel.h"
#include "commands/async.h"
+#include "commands/repack.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "port/pg_bitutils.h"
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 10be60011ad..9fbaa5c00f0 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -39,6 +39,7 @@
#include "commands/event_trigger.h"
#include "commands/explain_state.h"
#include "commands/prepare.h"
+#include "commands/repack.h"
#include "common/pg_prng.h"
#include "jit/jit.h"
#include "libpq/libpq.h"
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 2b609bfc824..5f8c766c4be 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -26,7 +26,6 @@
#include "catalog/toasting.h"
#include "commands/alter.h"
#include "commands/async.h"
-#include "commands/cluster.h"
#include "commands/collationcmds.h"
#include "commands/comment.h"
#include "commands/conversioncmds.h"
@@ -46,6 +45,7 @@
#include "commands/proclang.h"
#include "commands/propgraphcmds.h"
#include "commands/publicationcmds.h"
+#include "commands/repack.h"
#include "commands/schemacmds.h"
#include "commands/seclabel.h"
#include "commands/sequence.h"
diff --git a/src/include/commands/cluster.h b/src/include/commands/repack.h
similarity index 90%
rename from src/include/commands/cluster.h
rename to src/include/commands/repack.h
index d6b62c747e8..85061158b0c 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/repack.h
@@ -1,17 +1,17 @@
/*-------------------------------------------------------------------------
*
- * cluster.h
- * header file for postgres cluster command stuff
+ * repack.h
+ * header file for the REPACK command
*
* Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
* Portions Copyright (c) 1994-5, Regents of the University of California
*
- * src/include/commands/cluster.h
+ * src/include/commands/repack.h
*
*-------------------------------------------------------------------------
*/
-#ifndef CLUSTER_H
-#define CLUSTER_H
+#ifndef REPACK_H
+#define REPACK_H
#include "nodes/parsenodes.h"
#include "parser/parse_node.h"
@@ -52,4 +52,4 @@ extern void finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
MultiXactId cutoffMulti,
char newrelpersistence);
-#endif /* CLUSTER_H */
+#endif /* REPACK_H */
--
2.47.3
--brnevsqjnuzpyok4
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment;
filename="v50-0003-Add-CONCURRENTLY-option-to-REPACK-command.patch"
^ permalink raw reply [nested|flat] 839+ messages in thread
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2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-25 11:48 [PATCH v1 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-07-26 10:49 [PATCH v3 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-08-09 07:56 [PATCH v4 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-02 06:32 [PATCH v5 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-22 04:53 [PATCH v7 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-25 05:01 [PATCH v8 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-04 05:51 [PATCH v9 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-10-22 02:22 [PATCH v10 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-11-08 06:57 [PATCH v11 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-12-04 11:23 [PATCH v12 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-01-22 09:45 [PATCH v13 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-02-28 13:59 [PATCH v14 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-03-28 10:30 [PATCH v15 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-04-28 11:00 [PATCH v17 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-11 07:11 [PATCH v18 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-14 23:26 [PATCH v19 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-05-24 02:26 [PATCH v20 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-08-26 04:32 [PATCH v21 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-09-19 04:48 [PATCH v22 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-10-25 03:56 [PATCH v23 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-19 06:06 [PATCH v24 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-21 06:19 [PATCH v25 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 12:44 [PATCH v26 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2024-12-30 23:53 [PATCH v27 6/9] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2026-03-31 16:55 [PATCH v50 2/8] Rename cluster.c/h -> repack.c/h Álvaro Herrera <[email protected]>
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